Detection of 26 Drugs of Abuse and Metabolites in Quantitative Dried Blood Spots by Liquid Chromatography-Mass Spectrometry.

A method was developed for the determination of 26 drugs of abuse from different classes, including illicit drugs in quantitative dried blood spots (qDBSs), with the aim to provide a convenient method for drug testing by using only 10 µL of capillary blood. A satisfactory limit of quantification (LOQ) of 2.5 ng/mL for 9 of the compounds and 5 ng/mL for 17 of the compounds and a limit of detection (LOD) of 0.75 ng/mL for 9 of the compounds and 1.5 ng/mL for 17 of the compounds were achieved for all analytes. Reversed-phase liquid chromatography was applied on a C18 column coupled to MS, providing selective detections with both +ESI and -ESI modes. Extraction from the qDBS was performed using AcN-MeOH, 1:1 (v/v), with recovery ranging from 84.6% to 106%, while no significant effect of the hematocrit was observed. The studied drugs of abuse were found to be stable over five days under three different storage conditions (at ambient temperature 21 °C, at -20 °C, and at 35 °C), thus offering a highly attractive approach for drug screening by minimally invasive sampling for individuals that could find application in forensic toxicology analysis.

Dried urine spot (DUS) applied for sampling prior to the accurate HILIC-MS/MS determination of 14 amino acids.

Urine amino acid analysis has proven valuable for an array of clinical or nutritional studies. However, transportation of liquid urine sample shows certain disadvantages, such as possible leakage, need for cold chain and thus higher costs for their transport. Utilization of dried urine spots (DUS) can offer an interesting alternative. In the present study, a method was developed for the determination of 14 amino acids in DUS including the testing of in-house collection device and drying of the sample before analysis. Normal filter paper was tested as the means for sample collection. Absorption and extraction experiments were performed on 3 different types of filter paper, with 3 different extraction solvents and two different solvent volumes. The solvents used were mixtures of common analytical solvents (methanol, water, acetonitrile) using total volumes of 1 mL and 1.5 mL. Finally, 1 mL of acetonitrile: methanol: water 40:40:20 (v/v/v) was chosen as the optimal system. Analysis was performed on a UHPLC-MS system, using stable isotope labeled internal standards. Method validation included the study of limits of detection (LOD) and quantification (LOQ), linearity ranges, precision, matrix effect, extraction recovery, precision, and stability for each analyte. The obtained results were satisfactory, thus enabling application of the proposed method as an alternative to the analysis of liquid urine. Further utilization of DUS can offer advantages by enabling patient centric sampling even in long distances far from the analytical laboratories.

An interview with Bioanalysis: speaking with the 2023 Reid bursary award winners - part 2.

The 25th edition of the International Reid Bioanalytical Forum (REID) was held at the Cambridge Belfry (Cambourne, UK) between 4 and 7 September 2023 and hosted approximately 100 delegates, the majority of whom were attending the event for their first time.REID encourages early-career researchers to present their work and have a bursary program to help provide them support. At the 2023 event, REID welcomed 15 bursary winners to provide them with the opportunity to participate in their first international meeting, network with their peers and make their first oral, or poster presentation. The bursary winners also had the opportunity to interview with the Bioanalysis journal and their responses to the interview questions are transcribed below in this second part of two.

Gastric Fluid Metabolomics Predicting the Need for Surfactant Replacement Therapy in Very Preterm Infants Results of a Case-Control Study.

Respiratory distress syndrome (RDS) is a major morbidity of prematurity. In this case-control study, we prospectively evaluated whether untargeted metabolomic analysis (gas chromatography-mass spectrometry) of the gastric fluid could predict the need for surfactant in very preterm neonates. 43 infants with RDS necessitating surfactant (cases) were compared with 30 infants who were not treated with surfactant (controls). Perinatal-neonatal characteristics were recorded. Significant differences in gastric fluid metabolites (L-proline, L-glycine, L-threonine, acetyl-L-serine) were observed between groups, but none could solely predict surfactant administration with high accuracy. Univariate analysis revealed significant predictors of surfactant administration involving gastric fluid metabolites (L-glycine, acetyl-L-serine) and clinical parameters (gestational age, Apgar scores, intubation in the delivery room). Multivariable models were constructed for significant clinical variables as well as for the combination of clinical variables and gastric fluid metabolites. The AUC value of the first model was 0.69 (95% CI 0.57-0.81) and of the second, 0.76 (95% CI 0.64-0.86), in which acetyl-L-serine and intubation in the delivery room were found to be significant predictors of surfactant therapy. This investigation adds to the current knowledge of biomarkers in preterm neonates with RDS, but further research is required to assess the predictive value of gastric fluid metabolomics in this field.